The NSW deputy premier has refused to rule out limiting interstate travel from Victoria as the southern state continues to see an uptick in COVID-19 cases.
Victoria confirmed another 19 coronavirus cases on Sunday, taking to 160 the number of new cases in the state over the past week.
Most new Victorian cases came from family gatherings.
Despite Premier Gladys Berejiklian's persistent criticism of interstate travel restrictions imposed by the likes of South Australia and Queensland, Deputy Premier John Barilaro said NSW was watching the Victorian situation closely.
He didn't reject the idea of interstate travel restrictions and admitted Victoria's spike in COVID-19 cases was "worrying" and "a real threat".
"Maybe some sort of limits around travel, but maybe not closing the border as a whole ... it's more about who's coming across the border and what we will do about it," Mr Barilaro told the Seven Network on Monday.
Ms Berejiklian last week rejected any suggestion of restricting movement between NSW and Victoria, labelling domestic border closures "artificial".
She also said restrictions were thwarting movement, business and family reconnection as the state's unemployment rate hit 6.4 per cent.
NSW reported two new cases of coronavirus over the 24 hours to 8pm on Sunday, one in a hotel-quarantined traveller.
The other case was in a non-travelling man in his 30s from southwest Sydney, with the source of his infection still unknown.
"He's not travelled recently or attended any mass gatherings recently ... he's well and isolating at home," NSW Health's Dr Jeremy McAnulty said in a video statement.
No COVID-19 patients are currently in intensive care in NSW.
Victorian Health Minister Jenny Mikakos on Sunday announced a four-week state of emergency extension until July 19, with Monday's planned easing of restrictions postponed and gathering restrictions re-tightened.
Dr McAnulty discouraged travel to Victoria's six coronavirus hotspots - the local government areas of Hume, Casey, Brimbank, Moreland, Cardinia and Darebin - until COVID-19 community transmission was brought under control.
Australian Associated Press